There are so many types of diapers out there.
Back when I worked as a nurse on the ward, I changed a ton of adult diapers every single day, and even though “diapers” sounds like one category, the features really vary a lot by type.
The best diaper also depends on who’s wearing it. It’s the same with babies — there are tons of diapers out there, but the best one really depends on the individual kid.
This time, drawing on having tried nearly every diaper sold in Japan, plus experience with my own kids and my friends’ kids, I put together a detailed rundown on diapers.
- What actually matters when choosing a diaper
- Recommended diapers by stage, from newborn to potty training
- When to switch from tape to pants style
- How to tell when it’s time to size up
- Choosing diapers for outings and for saving money
- What Actually Matters When Choosing a Diaper?
- Our Family’s Diaper Flowchart (From Birth to Potty Training)
- Newborn Stage: Pampers Tape (From the Hospital)
- Birth to Before Rolling Over: Moony Tape S
- Moony Pants S: Around Rolling Over / Starting to Move
- A Quick Aside: Individual Differences in Growth
- Moony Pants M / Pampers M: Around Crawling and Starting to Walk
- A Quick Aside: Diapers We’ve Tried Over the Years
- How to Tell When It’s Time to Size Up
- Diaper Flowchart
- In Summary
What Actually Matters When Choosing a Diaper?
There are plenty of diaper comparison articles out there. Most of them seem to focus on absorption speed and capacity, but personally, I don’t put much weight on that.
That’s because the diapers sold in Japan are all high quality, and I don’t think there’s much of a real difference between them.
Instead, there’s something I came to see as important through working as a nurse.
It’s whether the leg and waist gathers fit snugly, and whether you’re using the right product and size for your baby’s body type.
My older son is on the slim side, and my younger son is on the chunkier side.
I’m putting together everything I know from my own experience, plus notes I’ve swapped with nurse friends!
Our Family’s Diaper Flowchart (From Birth to Potty Training)
Here’s our family’s diaper history, laid out in order.
I’ll go into detail on which diapers we used at each stage, and why we chose them.
Newborn Stage: Pampers Tape (From the Hospital)
During the newborn stage we used Pampers tape-style diapers. Mostly because we just kept using the ones we got from the hospital where I gave birth.
Honestly, anything works fine at this stage (lol). Using whatever you got from the hospital is the safest bet.
Since the baby’s just lying on their back, I don’t think it makes much difference which diaper you use.
In their first month, most newborns gain around 1kg (about 2.2 lbs). There’s individual variation, but growth is fast at this stage, so keep an eye out for whether the tape fit that used to work is starting to feel snug!
Birth to Before Rolling Over: Moony Tape S
Why We Chose Tape Style
While your baby is still just lying on their back, tape-style diapers are hands-down more convenient.
It’s much easier if you leave the old diaper on and slide the new one underneath before switching!
After undoing the old tape, gather both legs together with one hand near the belly button, lift up, and raise their hips.
That way you can wipe all the way up to their back cleanly.
Putting a little baby oil on the wipe before wiping keeps waste (which is alkaline) from sticking as easily next time, making cleanup easier.
Roll up the old diaper and tuck the used wipes inside it.
Then just pull everything dirty out from underneath, and you can slide the new diaper right on.
With boys, they often pee the second you take the diaper off (lol). Laying a wipe over that spot can save you!
Pants Style for Outings Too
Even during the size-S stage before our baby’s neck was steady, we’d switch to pants style for outings.
The reason is tape-style diapers shift around inside a baby carrier and leak more easily.
For the loose-stool stage, Moony (a Japanese diaper brand by Unicharm) is hands-down the one to get. The “loose-stool pocket” genuinely prevents back-leaks.
Even within the same brand, the size and tape-vs-pants packaging can be confusing, so watch out! My husband went to buy newborn tape diapers and mistakenly grabbed size-S pants instead based on the packaging.
A lot of people were surprised we’d already switched to pants style, but most of my nurse friends were using pants style too (lol).
Also, lifting your baby’s hips slightly the moment you sense a poop coming is a real trick for preventing poop leaks!
Moony Pants S: Around Rolling Over / Starting to Move
When to Switch From Tape to Pants?
The time to switch from tape to pants is once your baby starts moving around a lot.
Once they start rolling over or kicking their legs and you keep finding the tape has shifted, it’s time to switch.
Once they’re at this stage, changing a tape diaper starts getting difficult too.
- My older son → didn’t move much & could be changed anytime → tape
- My younger son → started moving early & was carried around a lot → switched to pants right away
So rather than going by “switch at X months,” it’s really about paying close attention to where your own kid is right now.
A Quick Aside: Individual Differences in Growth
Weight and height are two things with huge individual variation. Among kids I personally know, the biggest was 10kg (about 22 lbs) at 5 months old, and the smallest was under 8kg (about 17.6 lbs) at 2 years old.
Both kids are now healthy 4- and 5-year-olds with zero issues, but at the time, the public health nurse repeatedly told the parents they were giving too much or too little formula.
※Japan has robust public support where a public health nurse checks in on your baby’s growth on a regular basis. On the flip side, there’s also a strong tendency to focus heavily on the “growth curve” for height and weight — if your baby is even slightly off the average, you may get pointed out for it, or asked to report exactly how many milliliters of formula they’re drinking.
Public health nurses are doing their jobs carefully by the book, so their guidance can sometimes come across as strict.
I might get scolded for saying this, but honestly, you don’t need to worry about it (lol).
The growth curve is a real metric, but,
whether your baby is crying, laughing, drinking, and going to the bathroom every day matters so much more.
There are plenty of other kids way outside the growth curve too — like a mixed-heritage kid I know who was already wearing a size 26.5cm (about US 8.5) shoe by the time they started elementary school.
For diaper sizing too, I really hope you’ll trust your own eyes rather than going with what everyone else says or what’s supposedly “the one.”
Moony Pants M / Pampers M: Around Crawling and Starting to Walk
Once you hit the M size stage, poop frequency settles down, and as solid foods progress, the texture of poop changes too.
Once you’ve graduated from needing the loose-stool pocket, this is the stage where the best-fitting diaper starts to depend more on your kid’s leg thickness, belly size, and even their sex.
For us, our baby started crawling not long after sitting up, and size M pants were just right around that time.
By the way, for our younger son, carrying around a different diaper size when out and about felt like a hassle, so at this stage we already had him in size L — the same as his 2-year-old older brother (lol)
A Quick Aside: Diapers We’ve Tried Over the Years
So far I’ve covered Pampers and Moony, but over the years we’ve also tried every major diaper brand, including GOO.N (a Japanese diaper brand by Daio Seishi/Elleair), Merries (a Japanese diaper brand by Kao), and Mamy Poko (a diaper brand by Unicharm, also sold across Asia).
Here’s a quick rundown of what stood out about each.
| Moony | Gathers fit snugly. Feels a bit tight around the belly. Best-in-class loose-stool pocket. |
| Pampers | Absorbent core runs lengthwise. Soft against the skin. Gathers don’t tend to cause itching. |
| Merries | Absorbent core runs widthwise. May leak more easily around the front for boys. Soft against the skin. Gathers don’t tend to cause itching. |
| GOO.N | A bit cheaper. Well-balanced overall. A disaster if it ends up in the washing machine (lol). |
| Mamy Poko | The cheapest option. Gathers run loose & can cause itching. Not great for slimmer kids. |
When our older son was little, we bought a huge stash of GOO.N diapers during a Rakuten Super Sale and used them for over a year. A few of them ended up going through the washing machine by accident, and the little polymer beads inside made such a mess to clean up that we stopped using them.
Pampers uses a fiber-based absorbent polymer, so even if it gets soaked through or torn, there’s no gel scattering everywhere, and cleanup was easy. That’s when we switched over to Pampers.
I assumed I was the only one putting laundry in the machine, but it turns out our kids had been “helpfully” tossing their used diapers in there too (lol). Keep an eye out for that.
How to Buy Diapers Cheap
Time it around a Rakuten Super Sale, or use Amazon’s subscribe-and-save!
I think most kids don’t stay in size S for very long. With a subscription, there’s a risk you forget to cancel after they’ve sized out, so we only put size L on Amazon’s subscribe-and-save!
Pampers Baby Dry Diapers
Subscribe-and-save recommended! /
How to Tell When It’s Time to Size Up
The moment to size up pants-style diapers is when they start feeling leaky or snug.
As sizes go up, you get fewer diapers per pack, and the per-diaper cost goes up too.
When we were on the fence about sizing up, I’d use the bigger size for outings and the smaller size on days we stayed home.
Pampers Pants L: Walking and Running Stage
By this stage, I think you’re basically a diaper master without needing anyone’s advice (lol).
What comes up new around this time is “nighttime diapers.” Bigger single-void volume and pee building up overnight are the main reasons for leaks, so switching to something packed with more absorbent polymer can save you from that dreaded “the sheets are soaked!!” moment in the morning.
Here’s the quick summary.
Most leak-proof → Oyasumi Man
Most compact → Pampers overnight pants
Skip this one → Mamy Poko overnight leak-proof pants
I put together a separate article on this topic, so definitely check it out!
Diaper Flowchart
Here’s a summary of the diapers we used, organized by stage.
My personal recommendation: Moony through size S, then Pampers from size M onward.
| Newborn | Just use whatever you start with! They’ll size out fast, so you may not even need to buy more. Wait as long as you can before stocking up! |
| Moony Size S Tape | |
| Moony Size S Pants | |
| Pampers Size M Pants | |
| Pampers Size L | |
| Pampers Overnight Size M (Pants) | |
| Pampers Overnight Size L |
Diaper prices have roughly doubled since our older son was born. For sizes you’ll definitely go through a lot of, like L, it might be worth stocking up.
In Summary
The key to choosing diapers is adjusting to your kid’s movement, body type, and lifestyle as they grow.
Even between siblings, when to switch to what can be totally different.
I hope this article helps you find the right diaper for your own kid!
Thanks so much for reading all the way to the end!
